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Project Name: Gila Bend Area Drainage Master Plan Update


Project Manager: Ra'Desha Williams
Contact by phone at or by email

Project is in Supervisor District:

  • District 1: False
  • District 2: False
  • District 3: False
  • District 4: False
  • District 5: True

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Project Type: Study

Project Description:

Gila Bend ADMP Update (2015-present)
Off-site hydrology was updated using the current NOAA 14 rainfall depths. The on-site hydrology was analyzed using two-dimensional analysis to better determine where the stormwater is ponding, especially upstream of the Gila Bend Canal. The study area for the two-dimensional analysis includes the area south of Interstate 8 (for about 1.5 miles to the south), State Route 85 to the west, Indian Road to the north, and approximately Butterfield Trail to the east. The area is about eight square miles. The revised ADMP recommends focusing efforts on the Sand Tank Wash levee, the Bender Wash overchute over the Gila Bend Canal, and the Scott Avenue Wash levee. The District is currently working with the Town of Gila Bend to develop opportunities for funding these projects.

Original Gila Bend ADMP (completed in 2002)
The purpose of the original Gila Bend ADMP was:

  1. To identify existing drainage problems and to develop corrective measures.
  2. To develop an overall drainage plan that would provide a tool to ensure that future growth provides adequate stormwater conveyance without adversely impacting existing development.

The planning area covered approximately 48 square miles bounded by the Gila River to the north, Citrus Valley Road to the west, Barry Goldwater Gunnery Range to the south, and the section line east of the Gila Bend Municipal Airport to the east. At the time the study was initiated, there had been a considerable amount of land development interest in this area. The Gila Bend ADMP provides the town of Gila Bend with structural and non-structural recommendations to properly plan for the stormwater conveyance needs of the anticipated growth.

The ADMP identified three broad recommended solutions: a set of floodwater management tools for guiding future development, flood control structures to be implemented by development, and flood control structures to be publicly funded. The third component centers on recommended improvements on Sand Tank Wash, including reconstruction of the Sand Tank Wash levee upstream of the Gila Bend Canal, and construction of a Gila Bend Canal overchute on Bender Wash, a retention basin upstream of Interstate 8 and an upstream floodwater detention facility.

Last Updated: 5/22/2020 3:42:00 PM

Project Updates

Project Story Map
Posted On: 5/22/2020 3:33:04 PM

A story map was created to summarize the elements of the project and the District’s efforts with the public.

Additional Project Info
Posted On: 5/22/2020 3:31:13 PM

Over the last 50 years, several studies have been completed assessing the flood hazards experienced by the Town of Gila Bend. In April 2015, the District updated the hydrologic model and the mitigation plan for the Gila Bend Area Drainage Master Plan (ADMP) watershed.

The Flood Control District of Maricopa County recently conducted a flood hazard assessment of Gila Bend. These efforts included: 1) Data collection of documented historic flood events 2) Summary of past studies 3) Economic impacts of flooding and proposed improvements 4) Analysis of current mapped FEMA floodplains and actual rain and stream gage data 5) Refined evaluation of previously proposed flood control structures.

The intent of the economic loss data was to determine which component(s) had the biggest positive impact to the area to be protected, and thus should be constructed first if only partial funding is available. Of the non-full build scenarios, the analyses determined that constructing both levees had the biggest impact. The benefits were practically equal to the full scenario. Of the single component scenarios, only the Sand Tank Wash Levee had a positive benefit.

In June 2019, the District also submitted a grant application on behalf of the Town of Gila Bend; however, the Town was not awarded any dollars from FEMA at this time. In the meantime, the District will continue working with the Town of Gila Bend to address grant application provided by FEMA. After all comments have been addressed, the new application will be re-submitted to FEMA next year funding.

Public Meetings

There are no public meetings scheduled.

Project Documents

Document Name Description Document Type Filesize Posted On  
Project Map Map graphic of study area PDF .361 5/22/2020 3:38:12 PM View